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Linux/arch/powerpc/mm/mem.c

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  1 /*
  2  *  PowerPC version
  3  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  4  *
  5  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
  6  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
  7  *    Copyright (C) 1996 Paul Mackerras
  8  *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
  9  *
 10  *  Derived from "arch/i386/mm/init.c"
 11  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 12  *
 13  *  This program is free software; you can redistribute it and/or
 14  *  modify it under the terms of the GNU General Public License
 15  *  as published by the Free Software Foundation; either version
 16  *  2 of the License, or (at your option) any later version.
 17  *
 18  */
 19 
 20 #include <linux/export.h>
 21 #include <linux/sched.h>
 22 #include <linux/kernel.h>
 23 #include <linux/errno.h>
 24 #include <linux/string.h>
 25 #include <linux/gfp.h>
 26 #include <linux/types.h>
 27 #include <linux/mm.h>
 28 #include <linux/stddef.h>
 29 #include <linux/init.h>
 30 #include <linux/bootmem.h>
 31 #include <linux/highmem.h>
 32 #include <linux/initrd.h>
 33 #include <linux/pagemap.h>
 34 #include <linux/suspend.h>
 35 #include <linux/memblock.h>
 36 #include <linux/hugetlb.h>
 37 #include <linux/slab.h>
 38 #include <linux/vmalloc.h>
 39 
 40 #include <asm/pgalloc.h>
 41 #include <asm/prom.h>
 42 #include <asm/io.h>
 43 #include <asm/mmu_context.h>
 44 #include <asm/pgtable.h>
 45 #include <asm/mmu.h>
 46 #include <asm/smp.h>
 47 #include <asm/machdep.h>
 48 #include <asm/btext.h>
 49 #include <asm/tlb.h>
 50 #include <asm/sections.h>
 51 #include <asm/sparsemem.h>
 52 #include <asm/vdso.h>
 53 #include <asm/fixmap.h>
 54 #include <asm/swiotlb.h>
 55 #include <asm/rtas.h>
 56 
 57 #include "mmu_decl.h"
 58 
 59 #ifndef CPU_FTR_COHERENT_ICACHE
 60 #define CPU_FTR_COHERENT_ICACHE 0       /* XXX for now */
 61 #define CPU_FTR_NOEXECUTE       0
 62 #endif
 63 
 64 unsigned long long memory_limit;
 65 
 66 #ifdef CONFIG_HIGHMEM
 67 pte_t *kmap_pte;
 68 EXPORT_SYMBOL(kmap_pte);
 69 pgprot_t kmap_prot;
 70 EXPORT_SYMBOL(kmap_prot);
 71 
 72 static inline pte_t *virt_to_kpte(unsigned long vaddr)
 73 {
 74         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 75                         vaddr), vaddr), vaddr);
 76 }
 77 #endif
 78 
 79 int page_is_ram(unsigned long pfn)
 80 {
 81 #ifndef CONFIG_PPC64    /* XXX for now */
 82         return pfn < max_pfn;
 83 #else
 84         unsigned long paddr = (pfn << PAGE_SHIFT);
 85         struct memblock_region *reg;
 86 
 87         for_each_memblock(memory, reg)
 88                 if (paddr >= reg->base && paddr < (reg->base + reg->size))
 89                         return 1;
 90         return 0;
 91 #endif
 92 }
 93 
 94 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 95                               unsigned long size, pgprot_t vma_prot)
 96 {
 97         if (ppc_md.phys_mem_access_prot)
 98                 return ppc_md.phys_mem_access_prot(file, pfn, size, vma_prot);
 99 
100         if (!page_is_ram(pfn))
101                 vma_prot = pgprot_noncached(vma_prot);
102 
103         return vma_prot;
104 }
105 EXPORT_SYMBOL(phys_mem_access_prot);
106 
107 #ifdef CONFIG_MEMORY_HOTPLUG
108 
109 #ifdef CONFIG_NUMA
110 int memory_add_physaddr_to_nid(u64 start)
111 {
112         return hot_add_scn_to_nid(start);
113 }
114 #endif
115 
116 int arch_add_memory(int nid, u64 start, u64 size, bool for_device)
117 {
118         struct pglist_data *pgdata;
119         struct zone *zone;
120         unsigned long start_pfn = start >> PAGE_SHIFT;
121         unsigned long nr_pages = size >> PAGE_SHIFT;
122         int rc;
123 
124         pgdata = NODE_DATA(nid);
125 
126         start = (unsigned long)__va(start);
127         rc = create_section_mapping(start, start + size);
128         if (rc) {
129                 pr_warning(
130                         "Unable to create mapping for hot added memory 0x%llx..0x%llx: %d\n",
131                         start, start + size, rc);
132                 return -EFAULT;
133         }
134 
135         /* this should work for most non-highmem platforms */
136         zone = pgdata->node_zones +
137                 zone_for_memory(nid, start, size, 0, for_device);
138 
139         return __add_pages(nid, zone, start_pfn, nr_pages);
140 }
141 
142 #ifdef CONFIG_MEMORY_HOTREMOVE
143 int arch_remove_memory(u64 start, u64 size)
144 {
145         unsigned long start_pfn = start >> PAGE_SHIFT;
146         unsigned long nr_pages = size >> PAGE_SHIFT;
147         struct zone *zone;
148         int ret;
149 
150         zone = page_zone(pfn_to_page(start_pfn));
151         ret = __remove_pages(zone, start_pfn, nr_pages);
152         if (ret)
153                 return ret;
154 
155         /* Remove htab bolted mappings for this section of memory */
156         start = (unsigned long)__va(start);
157         ret = remove_section_mapping(start, start + size);
158 
159         /* Ensure all vmalloc mappings are flushed in case they also
160          * hit that section of memory
161          */
162         vm_unmap_aliases();
163 
164         return ret;
165 }
166 #endif
167 #endif /* CONFIG_MEMORY_HOTPLUG */
168 
169 /*
170  * walk_memory_resource() needs to make sure there is no holes in a given
171  * memory range.  PPC64 does not maintain the memory layout in /proc/iomem.
172  * Instead it maintains it in memblock.memory structures.  Walk through the
173  * memory regions, find holes and callback for contiguous regions.
174  */
175 int
176 walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
177                 void *arg, int (*func)(unsigned long, unsigned long, void *))
178 {
179         struct memblock_region *reg;
180         unsigned long end_pfn = start_pfn + nr_pages;
181         unsigned long tstart, tend;
182         int ret = -1;
183 
184         for_each_memblock(memory, reg) {
185                 tstart = max(start_pfn, memblock_region_memory_base_pfn(reg));
186                 tend = min(end_pfn, memblock_region_memory_end_pfn(reg));
187                 if (tstart >= tend)
188                         continue;
189                 ret = (*func)(tstart, tend - tstart, arg);
190                 if (ret)
191                         break;
192         }
193         return ret;
194 }
195 EXPORT_SYMBOL_GPL(walk_system_ram_range);
196 
197 #ifndef CONFIG_NEED_MULTIPLE_NODES
198 void __init initmem_init(void)
199 {
200         max_low_pfn = max_pfn = memblock_end_of_DRAM() >> PAGE_SHIFT;
201         min_low_pfn = MEMORY_START >> PAGE_SHIFT;
202 #ifdef CONFIG_HIGHMEM
203         max_low_pfn = lowmem_end_addr >> PAGE_SHIFT;
204 #endif
205 
206         /* Place all memblock_regions in the same node and merge contiguous
207          * memblock_regions
208          */
209         memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0);
210 
211         /* XXX need to clip this if using highmem? */
212         sparse_memory_present_with_active_regions(0);
213         sparse_init();
214 }
215 
216 /* mark pages that don't exist as nosave */
217 static int __init mark_nonram_nosave(void)
218 {
219         struct memblock_region *reg, *prev = NULL;
220 
221         for_each_memblock(memory, reg) {
222                 if (prev &&
223                     memblock_region_memory_end_pfn(prev) < memblock_region_memory_base_pfn(reg))
224                         register_nosave_region(memblock_region_memory_end_pfn(prev),
225                                                memblock_region_memory_base_pfn(reg));
226                 prev = reg;
227         }
228         return 0;
229 }
230 #else /* CONFIG_NEED_MULTIPLE_NODES */
231 static int __init mark_nonram_nosave(void)
232 {
233         return 0;
234 }
235 #endif
236 
237 static bool zone_limits_final;
238 
239 static unsigned long max_zone_pfns[MAX_NR_ZONES] = {
240         [0 ... MAX_NR_ZONES - 1] = ~0UL
241 };
242 
243 /*
244  * Restrict the specified zone and all more restrictive zones
245  * to be below the specified pfn.  May not be called after
246  * paging_init().
247  */
248 void __init limit_zone_pfn(enum zone_type zone, unsigned long pfn_limit)
249 {
250         int i;
251 
252         if (WARN_ON(zone_limits_final))
253                 return;
254 
255         for (i = zone; i >= 0; i--) {
256                 if (max_zone_pfns[i] > pfn_limit)
257                         max_zone_pfns[i] = pfn_limit;
258         }
259 }
260 
261 /*
262  * Find the least restrictive zone that is entirely below the
263  * specified pfn limit.  Returns < 0 if no suitable zone is found.
264  *
265  * pfn_limit must be u64 because it can exceed 32 bits even on 32-bit
266  * systems -- the DMA limit can be higher than any possible real pfn.
267  */
268 int dma_pfn_limit_to_zone(u64 pfn_limit)
269 {
270         enum zone_type top_zone = ZONE_NORMAL;
271         int i;
272 
273 #ifdef CONFIG_HIGHMEM
274         top_zone = ZONE_HIGHMEM;
275 #endif
276 
277         for (i = top_zone; i >= 0; i--) {
278                 if (max_zone_pfns[i] <= pfn_limit)
279                         return i;
280         }
281 
282         return -EPERM;
283 }
284 
285 /*
286  * paging_init() sets up the page tables - in fact we've already done this.
287  */
288 void __init paging_init(void)
289 {
290         unsigned long long total_ram = memblock_phys_mem_size();
291         phys_addr_t top_of_ram = memblock_end_of_DRAM();
292         enum zone_type top_zone;
293 
294 #ifdef CONFIG_PPC32
295         unsigned long v = __fix_to_virt(__end_of_fixed_addresses - 1);
296         unsigned long end = __fix_to_virt(FIX_HOLE);
297 
298         for (; v < end; v += PAGE_SIZE)
299                 map_page(v, 0, 0); /* XXX gross */
300 #endif
301 
302 #ifdef CONFIG_HIGHMEM
303         map_page(PKMAP_BASE, 0, 0);     /* XXX gross */
304         pkmap_page_table = virt_to_kpte(PKMAP_BASE);
305 
306         kmap_pte = virt_to_kpte(__fix_to_virt(FIX_KMAP_BEGIN));
307         kmap_prot = PAGE_KERNEL;
308 #endif /* CONFIG_HIGHMEM */
309 
310         printk(KERN_DEBUG "Top of RAM: 0x%llx, Total RAM: 0x%llx\n",
311                (unsigned long long)top_of_ram, total_ram);
312         printk(KERN_DEBUG "Memory hole size: %ldMB\n",
313                (long int)((top_of_ram - total_ram) >> 20));
314 
315 #ifdef CONFIG_HIGHMEM
316         top_zone = ZONE_HIGHMEM;
317         limit_zone_pfn(ZONE_NORMAL, lowmem_end_addr >> PAGE_SHIFT);
318 #else
319         top_zone = ZONE_NORMAL;
320 #endif
321 
322         limit_zone_pfn(top_zone, top_of_ram >> PAGE_SHIFT);
323         zone_limits_final = true;
324         free_area_init_nodes(max_zone_pfns);
325 
326         mark_nonram_nosave();
327 }
328 
329 void __init mem_init(void)
330 {
331         /*
332          * book3s is limited to 16 page sizes due to encoding this in
333          * a 4-bit field for slices.
334          */
335         BUILD_BUG_ON(MMU_PAGE_COUNT > 16);
336 
337 #ifdef CONFIG_SWIOTLB
338         swiotlb_init(0);
339 #endif
340 
341         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);
342         set_max_mapnr(max_pfn);
343         free_all_bootmem();
344 
345 #ifdef CONFIG_HIGHMEM
346         {
347                 unsigned long pfn, highmem_mapnr;
348 
349                 highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT;
350                 for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
351                         phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT;
352                         struct page *page = pfn_to_page(pfn);
353                         if (!memblock_is_reserved(paddr))
354                                 free_highmem_page(page);
355                 }
356         }
357 #endif /* CONFIG_HIGHMEM */
358 
359 #if defined(CONFIG_PPC_FSL_BOOK3E) && !defined(CONFIG_SMP)
360         /*
361          * If smp is enabled, next_tlbcam_idx is initialized in the cpu up
362          * functions.... do it here for the non-smp case.
363          */
364         per_cpu(next_tlbcam_idx, smp_processor_id()) =
365                 (mfspr(SPRN_TLB1CFG) & TLBnCFG_N_ENTRY) - 1;
366 #endif
367 
368         mem_init_print_info(NULL);
369 #ifdef CONFIG_PPC32
370         pr_info("Kernel virtual memory layout:\n");
371         pr_info("  * 0x%08lx..0x%08lx  : fixmap\n", FIXADDR_START, FIXADDR_TOP);
372 #ifdef CONFIG_HIGHMEM
373         pr_info("  * 0x%08lx..0x%08lx  : highmem PTEs\n",
374                 PKMAP_BASE, PKMAP_ADDR(LAST_PKMAP));
375 #endif /* CONFIG_HIGHMEM */
376 #ifdef CONFIG_NOT_COHERENT_CACHE
377         pr_info("  * 0x%08lx..0x%08lx  : consistent mem\n",
378                 IOREMAP_TOP, IOREMAP_TOP + CONFIG_CONSISTENT_SIZE);
379 #endif /* CONFIG_NOT_COHERENT_CACHE */
380         pr_info("  * 0x%08lx..0x%08lx  : early ioremap\n",
381                 ioremap_bot, IOREMAP_TOP);
382         pr_info("  * 0x%08lx..0x%08lx  : vmalloc & ioremap\n",
383                 VMALLOC_START, VMALLOC_END);
384 #endif /* CONFIG_PPC32 */
385 }
386 
387 void free_initmem(void)
388 {
389         ppc_md.progress = ppc_printk_progress;
390         free_initmem_default(POISON_FREE_INITMEM);
391 }
392 
393 #ifdef CONFIG_BLK_DEV_INITRD
394 void __init free_initrd_mem(unsigned long start, unsigned long end)
395 {
396         free_reserved_area((void *)start, (void *)end, -1, "initrd");
397 }
398 #endif
399 
400 /*
401  * This is called when a page has been modified by the kernel.
402  * It just marks the page as not i-cache clean.  We do the i-cache
403  * flush later when the page is given to a user process, if necessary.
404  */
405 void flush_dcache_page(struct page *page)
406 {
407         if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
408                 return;
409         /* avoid an atomic op if possible */
410         if (test_bit(PG_arch_1, &page->flags))
411                 clear_bit(PG_arch_1, &page->flags);
412 }
413 EXPORT_SYMBOL(flush_dcache_page);
414 
415 void flush_dcache_icache_page(struct page *page)
416 {
417 #ifdef CONFIG_HUGETLB_PAGE
418         if (PageCompound(page)) {
419                 flush_dcache_icache_hugepage(page);
420                 return;
421         }
422 #endif
423 #if defined(CONFIG_8xx) || defined(CONFIG_PPC64)
424         /* On 8xx there is no need to kmap since highmem is not supported */
425         __flush_dcache_icache(page_address(page));
426 #else
427         if (IS_ENABLED(CONFIG_BOOKE) || sizeof(phys_addr_t) > sizeof(void *)) {
428                 void *start = kmap_atomic(page);
429                 __flush_dcache_icache(start);
430                 kunmap_atomic(start);
431         } else {
432                 __flush_dcache_icache_phys(page_to_pfn(page) << PAGE_SHIFT);
433         }
434 #endif
435 }
436 EXPORT_SYMBOL(flush_dcache_icache_page);
437 
438 void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
439 {
440         clear_page(page);
441 
442         /*
443          * We shouldn't have to do this, but some versions of glibc
444          * require it (ld.so assumes zero filled pages are icache clean)
445          * - Anton
446          */
447         flush_dcache_page(pg);
448 }
449 EXPORT_SYMBOL(clear_user_page);
450 
451 void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
452                     struct page *pg)
453 {
454         copy_page(vto, vfrom);
455 
456         /*
457          * We should be able to use the following optimisation, however
458          * there are two problems.
459          * Firstly a bug in some versions of binutils meant PLT sections
460          * were not marked executable.
461          * Secondly the first word in the GOT section is blrl, used
462          * to establish the GOT address. Until recently the GOT was
463          * not marked executable.
464          * - Anton
465          */
466 #if 0
467         if (!vma->vm_file && ((vma->vm_flags & VM_EXEC) == 0))
468                 return;
469 #endif
470 
471         flush_dcache_page(pg);
472 }
473 
474 void flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
475                              unsigned long addr, int len)
476 {
477         unsigned long maddr;
478 
479         maddr = (unsigned long) kmap(page) + (addr & ~PAGE_MASK);
480         flush_icache_range(maddr, maddr + len);
481         kunmap(page);
482 }
483 EXPORT_SYMBOL(flush_icache_user_range);
484 
485 /*
486  * This is called at the end of handling a user page fault, when the
487  * fault has been handled by updating a PTE in the linux page tables.
488  * We use it to preload an HPTE into the hash table corresponding to
489  * the updated linux PTE.
490  * 
491  * This must always be called with the pte lock held.
492  */
493 void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
494                       pte_t *ptep)
495 {
496 #ifdef CONFIG_PPC_STD_MMU
497         /*
498          * We don't need to worry about _PAGE_PRESENT here because we are
499          * called with either mm->page_table_lock held or ptl lock held
500          */
501         unsigned long access = 0, trap;
502 
503         /* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
504         if (!pte_young(*ptep) || address >= TASK_SIZE)
505                 return;
506 
507         /* We try to figure out if we are coming from an instruction
508          * access fault and pass that down to __hash_page so we avoid
509          * double-faulting on execution of fresh text. We have to test
510          * for regs NULL since init will get here first thing at boot
511          *
512          * We also avoid filling the hash if not coming from a fault
513          */
514         if (current->thread.regs == NULL)
515                 return;
516         trap = TRAP(current->thread.regs);
517         if (trap == 0x400)
518                 access |= _PAGE_EXEC;
519         else if (trap != 0x300)
520                 return;
521         hash_preload(vma->vm_mm, address, access, trap);
522 #endif /* CONFIG_PPC_STD_MMU */
523 #if (defined(CONFIG_PPC_BOOK3E_64) || defined(CONFIG_PPC_FSL_BOOK3E)) \
524         && defined(CONFIG_HUGETLB_PAGE)
525         if (is_vm_hugetlb_page(vma))
526                 book3e_hugetlb_preload(vma, address, *ptep);
527 #endif
528 }
529 
530 /*
531  * System memory should not be in /proc/iomem but various tools expect it
532  * (eg kdump).
533  */
534 static int __init add_system_ram_resources(void)
535 {
536         struct memblock_region *reg;
537 
538         for_each_memblock(memory, reg) {
539                 struct resource *res;
540                 unsigned long base = reg->base;
541                 unsigned long size = reg->size;
542 
543                 res = kzalloc(sizeof(struct resource), GFP_KERNEL);
544                 WARN_ON(!res);
545 
546                 if (res) {
547                         res->name = "System RAM";
548                         res->start = base;
549                         res->end = base + size - 1;
550                         res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
551                         WARN_ON(request_resource(&iomem_resource, res) < 0);
552                 }
553         }
554 
555         return 0;
556 }
557 subsys_initcall(add_system_ram_resources);
558 
559 #ifdef CONFIG_STRICT_DEVMEM
560 /*
561  * devmem_is_allowed(): check to see if /dev/mem access to a certain address
562  * is valid. The argument is a physical page number.
563  *
564  * Access has to be given to non-kernel-ram areas as well, these contain the
565  * PCI mmio resources as well as potential bios/acpi data regions.
566  */
567 int devmem_is_allowed(unsigned long pfn)
568 {
569         if (page_is_rtas_user_buf(pfn))
570                 return 1;
571         if (iomem_is_exclusive(PFN_PHYS(pfn)))
572                 return 0;
573         if (!page_is_ram(pfn))
574                 return 1;
575         return 0;
576 }
577 #endif /* CONFIG_STRICT_DEVMEM */
578 

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